1. (A TECHNICAL SEMINAR REPORT)
WIRELESS POWER TRANSMISSION AND
RECEPTION USING SOLAR POWER SATELLITES AND
RECTENNA
PRESENTED BY:GAURAV
SINHA
2. INTRODUCTION
1. SOLAR POWER IS - INEXAUSTIBLE(RENEWABLE)
ENERGY RESOURCE.
2. WE CAN, IN FACT DIRECTLY CONVERT SOLAR
ENERGY INTO ELECTRICAL ENERGY WITH THE USE
OF SOLAR CELLS, BUT SUNLIGHT DIFFUSES AT
NIGHT TIME FROM THE EARTH.
3. IF THE NEED ARISES FOR 24 HOURS POWER
SUPPLY, WE ARE HELPLESS.
4. THE SOLUTION IS WIRELESS POWER
TRANSMISSION FROM SPACE THROUGH A SYSTEM
CONSISTING OF SPS (SOLAR POWER SATELLITE)
4. PRINCILPLE
1.Modern techniques enables us to create a platform in
space carrying solar batteries, generators converting
electric current worked out by them into the
Electromagnetic field energy of ten centimeter range
(microwaves) and antenna forming electromagnetic
wave beam.
2.On the earth, the other antenna (rectenna) receives
the beam and it is converted into electric current again.
3.The principal advantage of the space location is its
independence of weather and day-night cycle and is
pollution free.
5. 4.It is shown that a correct choice of the field distribution on
the radiation antenna allows us to increase the wireless
power transmission efficiency and to lessen its cost(As
Space Solar Power Stations are costly because of sheer
size of Radiating & Receiving Antennas.).
5.Antenna and Rectenna sizes are chosen such that the
rectenna is situated in the antenna’s Fresnel’s area.
6.This Design has many Advantages from Environmental
point of view.
7. OVERVIEW OF SYSTEM DESIGN
*Construction of spacetenna and rectenna to increase the
effectiveness of WPT.
I.SPACETENNA:(THE ANTENNA ON SATELLITE)
1.Spacetenna is a triangular prism with a length of 800 m
and sides of 100 m.
2.The
main
axis
lies
in
the
north-south
direction, perpendicular to the direction of orbital motion.
3. The transmitting antenna on the horizontal under-surface
faces the Earth, and the other two sides of the prism
carry solar arrays.
8. 4.The faces of the prism are embedded with photovoltaic
cells. These Photovoltaic cells would convert sunlight into
electrical current, which would, in turn, power an onboard
microwave generator.
5. The Microwave thus produced Travels through Atmosphere
& is collected by RECTENNAS on Earth.
6. The Spacetenna has a square shape whose dimension is
132 meters by 132 meters and which is regularly filled with
1936 segments of sub array.
7. The sub array is considered to be a unit of phase control
and also a square shape whose edges are 3 meters. It
contains 1320 units of cavity-backed slot antenna element
and DC-RF circuit. Therefore, there will be about 2.6 million
antenna elements in the spacetenna.
10. 8.The spacetenna is composed of pilot signal receiving
antennas followed by detectors finding out the location of the
rectenna on the earth, power transmission antenna elements
and phase control systems.
9. Moreover, the pilot signal frequency and a frequency for the
energy transmission are different from each other.
10. Using two kinds of frequency for the power transmission
and the pilot signal prevents each other from interfering and
makes it possible to find out the accurate direction of a
specified rectenna.
11. II.RECTENNNA :(RECTIFYING ANTENNA)
1.A Rectenna can be considered as a base station for a geostationary satellite. Microwaves of 2.45 GHz frequency are used
to transmit power from the satellite to the rectenna.
2. It consists of a mesh of an array of dipole antennas connected
to diodes to convert the radio frequency energy to DC voltage,
which is then converted to regular AC electricity and wired to
homes, factories, etc.
3. A simple reflector plane could be added to the mesh to
improve the efficiency to 50%.
13. Orbit Selection
1.A 1100km altitude equatorial orbit will be used. This choice
minimizes the transportation cost and the distance of power
transmission from space.
2. If it was in GEO (that is, 35,800 kilometers from Earth) then
the transmitting antenna would have to be 40 times larger
than a LEO one - or else the receiving antenna would have
to be 40 times larger.
3. So satellite has to orbit above the equator in order to have
frequent transmission opportunities. It transmits up to
10Mwatts of radio-frequency power. Ten satellites placed
evenly around the orbit would require only nine minutes of
storage capacity to provide continuous power.
15. Advantages
•Unaffected by day-night cycle, weather or seasons. Optimized
advances may enable 21 hour power supply per day.
•This is an eco-friendly, renewable and maintenance free energy
resource unlike the conventional fuels.
•As the equipment is positioned in space, it is occupies no land
area and remains unaffected by harsh weather conditions.
Rectennas can share land with farms.
•The spacetenna could direct energy to any rectenna on earth
within the range of its steering angle, which could satisfy the
energy requirements of all the equatorial countries.
•Waste heat is re-radiated back into space, instead of warming the
biosphere.
16. Conclusion
Synthesizing the wireless power transmission, it can be
concluded that to make the SPS concept commercially
viable, it becomes a priority to improve its efficiency and the
cost per watt. This can be achieved by:
1.Placing the Rectenna within the Fresnel area of
the transmitter.
2. Placing the transmitting antenna in the LEO
orbit to reduce installation cost and the distance of
transmission.
17. 3. Using a discontinuous equidistant array with quasi
Gauss distribution.
4. Using a discontinuous non-equidistant array with
uniform distribution.
BOTTOMLINE: Will be a boon as we are running
out of fossil fuels.